SALT STRESS AFFECTS IN-VITRO GROWTH AND IN-SITU SYMBIOSES OF ECTOMYCORRHIZAL FUNGI

Ten isolates of six species of ectomycorrhizal fungi were grown in vitro at nine concentrations of three sodium salts (NaCl, Na2SO4, Na3C6H5O7) for 4 weeks. Colony diamater, biomass and protein content of fungi were evaluated. Isolates of Pisolithus tinctorius and Suillus luteus were more tolerant of NaCl and Na2SO4 than of Na3C6H5O7. Fungi in the genera Cenococcum, Laccaria, and Thelephora were highly intolerant of Na3C6H5O7 and Na2SO4 in Vitro. Biomass and protein content of fungi generally declined with increasing substrate salinity in solution culture. In situ ectomycorrhizal colonization by Laccara laccata and P. tinctorius and the dry weight of Pinus taeda seedlings were significantly reduced by 80 mM NaCl after 14 weeks. Only select ectomycorrhizal fungi appear capable of growth and symbiosis in saline soils.